1) Embryo transfer involves placing embryos into the uterus of a female with the intent to establish a pregnancy. This can involve fresh or frozen embryos. 2) The first successful embryo transfers were conducted in rabbits in 1890 and then various livestock including sheep, cattle, pigs, and water buffalo. The first "test tube baby" was born in 1978. 3) The embryo transfer process involves preparing the uterus, using catheters to deposit embryos, and confirming pregnancy. Embryos are typically transferred at the 2-4 cell stage. Applications include genetic improvement and conservation of endangered species.

1. EXPERIMENTAL
EMBRYOLOGY
EMBRYO TRANSFER
DONE BY:
NIVETHA.M
1st YEAR
M.Sc ZOOLOGY

2. INTRODUCTION
• Embryo transfer refers to a step in the process of
assisted reproduction (IVF) in which embryos are
placed into the uterus of a female with the intent to
establish a pregnancy.
• ET can be of two types:
1)Fresh embryo transfer- fresh from fertilized
egg cells of the same menstrual cycle.
2)Frozen embryo transfer- they have been
generated in a preceding cycle and undergone
embryo cryopreservation, and are thawed just prior
to the transfer.

3. HISTORY OF EMBRYO TRANSFER
• The first successful embryo transfer was carried out
in rabbit (1890) by Heap.
• First lamb by ETT- 1949 by Berry.
• First calf by ETT- 1951 by Willet et al.
• In swine – 1951 by Kvansnickii.
• In Asian buffalo – 1983 by Drost et al.
• University of Sydney claims first sex sorted pregnancy
by embryo transfer-2002

4. STEPS INVOLVED IN EMBRYO TRANSFER
1) UTERINE PREPARATION
• In a stimulated or a cycle where a "frozen" embryo is
transferred, the recipient woman could be given first
oestrogen preparations (about 2 weeks), then a
combination of oestrogen and progesterone so that
the lining becomes receptive for the embryo.

5. NORMAL AND THICK UTERINE WALL

6. 2) CATHETERS
• There are different types of catheters used in ET. They vary from each
other by,
• Volume of Media.
• constitution of the medium loaded in the catheter.
• Loading with using fluid alone, or mixture of air and fluid in the
catheter.
• There are two common techniques in catheter loading :
1. Air loaded method
2. Continuous fluid method

7. SOFT AND RIGID CATHETERS

8. The best stage to transfer of embryos to uterus
is 2-4 celled stage.

9. ET- TECHNIQUE
• The embryo transfer procedure starts by placing a
bivalve speculum in the vagina to visualize the cervix,
which is cleansed with saline solution or culture
media.

10. Trans-Vaginal Embryo Transfer
• There are two types of embryo transfer methods:
1)Blind Insertion
• The loaded ET catheter is introduced through the cervix to
pass the internal os and then gently advanced in the mid-
uterine cavity and stopped from 1–2 cm short of the fundus.
• {Some patients experience suprapubic heaviness and
discomfort}. After 1-2 min, when this complaint disappears,
the embryos are ejected slowly.
• Catheter is left in situ for 30-60 sec.
• Pressure is kept on the plunger of the syringe while slowly
withdrawing the catheter out avoiding negative pressure.
• After ET the catheter is checked for any retained embryos. If
found, retransfer is done immediately.
• Then bed rest: 30 min.

11. TRANSFERING EMBRYO

12. 2)U.S guidance- ET
• The clinician use of abdominal ultrasound in addition of visualizing
the catheter is to straighten the uterovesical angle which my make
the insertion of the catheter easier.
• Under US guidance: outer sheath of (the labotect) ET catheter is
passed, just beyond the internal os.
• The inner sheath is loaded by the embryologist who then assist the
physician in threading the inner sheath into the external sheath.
• The inner catheter is slowly advanced by the physician, and the
embryos are deposited 1.0 cm from the fundus (mid uterine cavity).
• After 5–10 sec soft catheter removed first (pressure on the syringe
plunger maintained) while outer sheath withdrawn past internal os
Laboratory check.
• Rigid outer sheath removed and checked.
• The catheter is gently rotated and removed (with keep the plunger
of the catheter depressed until it had been completely removed
from the cervix) over 15 s.

14. CONT..
•After the embryo transfer process completion a pregnancy test has been carried
to confirm the success of IVF.
•The babies produced using these approaches are called test tube babies.
•The first test tube baby was born on July 25, 1978 and was named Louise Joy
Brown.
•The Nobel Prize of Medicine for the year 2010 was awarded to Robert G. Edwards
for this outstanding invention.
Louise Brown with her parents Robert G. Edwards with Louise

15. APPLICATIONS OF EMBRYO TRANSFER
• Faster genetic improvement.
• Genetic screening.
• Disease control.
• Import and export.
• Circumvention of infertility.
• Twinning in cattle.
• Conservation of endangered species.
• Research; production of clones and genetic engineering.

16. Disadvantages of ETT
• Can be cost prohibitive and success rates are less
than AI.
• Cost and maintenance of recipient females.
• Requires a technician with the skills to flush embryos
from the reproductive tract.
• Possible spread of disease through recipients.